1. Field of the Invention
The present invention relates to an electric cylindrical lock that can be unlocked by a key when a solenoid of the electric cylindrical lock malfunctions or when electricity service is unavailable.
2. Description of the Related Art
Cylindrical locks are convenient to handicapped people, but the hand-handicapped users still suffer from inserting a flat key into the keyhole of a cylindrical lock. Electric cylindrical locks are thus proposed to eliminate this drawback, but they bring other problems. Particularly, the door cannot be opened when the electricity is out of service or a solenoid of the cylindrical lock malfunctions.
It is, therefore, the primary object of the present invention to provide an electric cylindrical lock that can be unlocked by a key when a solenoid of the electric cylindrical lock malfunctions or when electricity service is unavailable.
An electric cylindrical lock in accordance with the present invention comprises:
a chassis;
an inner spindle attached to the chassis;
an inner handle operably connected to the inner spindle;
a latch assembly attached to the chassis and including a latch, the inner handle and the inner spindle being so arranged that rotation of the inner handle causes retraction of the latch;
an outer spindle attached to the chassis and having a first end and a second end, the outer spindle further including a slot;
an outer handle operably connected to the first end of the outer spindle, the outer handle and the outer spindle being so arranged that rotation of one of the outer spindle and the outer handle causes retraction of the latch;
a lock cylinder mounted in the outer handle;
a tubular seat mounted around the second end of the outer spindle and including a positioning groove aligned with the slot of the outer spindle;
a sleeve mounted in the outer spindle and including an end operably connected to the lock cylinder such that the sleeve rotates in the outer spindle when the lock cylinder is turned;
a pressing plate mounted in the outer spindle and including a first end and a second end, the first end of the pressing plate being operably connected to the sleeve such that the pressing plate moves along a longitudinal direction of the outer spindle when the sleeve rotates in response to turning of the lock cylinder;
a solenoid mounted in the tubular seat and including a first end and a second end, the first end of the solenoid being connected to the second end of the pressing plate to move therewith;
a locking plate mounted in the tubular seat, the locking plate including a protrusion releasably engaged in the positioning groove of the tubular seat; and
a spring attached between the second end of the solenoid and the locking plate;
wherein when the solenoid is energized, the electric cylindrical lock is in a locked state in which the protrusion of the locking plate is engaged in the positioning groove of the tubular seat;
wherein when the solenoid is de-energized, the locking plate is moved along the longitudinal direction of the outer spindle such that the protrusion of the locking plate is disengaged from the positioning groove of the tubular seat, thereby allowing unlatching by means of turning one of the inner handle and the outer handle; and
wherein when the solenoid is inoperable, the lock cylinder is turnable by a key to cause longitudinal movements of the solenoid, the pressing plate, and the sleeve which. in turn, causes the locking plate to move along the longitudinal direction of the outer spindle such that the protrusion of the locking plate is disengaged from the positioning groove of the tubular seat, thereby allowing unlatching by means of turning one of the inner handle and the outer handle.
The first end of the sleeve includes a substantially 8-shape opening and the lock cylinder includes a tailpiece engaged in the 8-shape opening. The sleeve includes an arcuate slot in a periphery thereof. The pressing plate includes a stem extending from a side thereof. The stem is received in the sleeve and includes a fixing hole. A pin extends through the arcuate slot and has an end anchored in the fixing hole. The sleeve further includes a protrusion that is slidably received in the slot of the outer spindle. The solenoid includes a hole and the locking plate includes a through-hole. A positioning rod extends through the through-hole of the locking plate, the spring, and secured in the hole of the solenoid to move therewith. The positioning rod includes an enlarged head to prevent excessive movement of the locking plate.
Other objects, advantages, and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.